New Way to Treat Deadly Heart Problem

Some people suffering from a life-threatening heart condition known as severe aortic stenosis could benefit from an experimental treatment that avoids open-heart surgery to replace the aortic valve, a new study indicates.

As many as 1.5 million Americans have aortic stenosis, a progressive narrowing of the aortic valve that prevents blood from being pumped from the heart to the body and brain. About 300,000 of these people have a sufficiently severe condition as to require an artificial replacement. But open-heart surgery can be too risky for about one out of three of these patients, many of whom are elderly. For them, there is currently no effective treatment.

The experimental therapy, developed by
Edwards Lifesciences
EW 0.67%
Corp., of Irvine, Calif., is designed to place a new aortic valve in position in the heart without major surgery. The replacement valve is attached to a catheter, which is threaded through blood vessels until it reaches the heart.

This artificial heart valve is designed to do the job of an aortic valve that fails to open and close properly.
Edwards Lifesciences

The study, funded by Edwards and published Wednesday by the New England Journal of Medicine, followed 358 elderly patients, with an average age of 83. Half of the participants received catheter-delivered valves. The rest didn't receive replacement valves. Instead their conditions were managed by various means, such as having their original valves widened with a tiny balloon.

After one year, 30.7% of the replacement-valve group had died. That was well below the 50.7% death rate among patients whose condition was managed without receiving new valves.

Catheter-delivered valves "should be the new standard of care" for patients who can't undergo open-heart surgery, concluded the study's authors, some of whom have ties to Edwards Lifesciences through consulting fees and other avenues.

But the study also showed a higher rate of stroke in patients receiving the catheter-delivered replacement valves. Within 30 days of the procedure, 5% of these patients had had a major stroke, compared with 1.1% of patients whose conditions were merely managed. There was also a higher risk of vascular problems like bleeding for patients receiving the replacement valves.

"It was fair to say the stroke rate was higher than what everyone was expecting" and "several times higher than you would like," said Craig Smith, cardiac surgeon at New York-Presbyterian Hospital/Columbia University Medical Center and a co-principal investigator for the study. But given the risks these elderly and frail patients face if their valves aren't replaced, he said, it's also "an acceptable price to pay."

Edwards Lifesciences' replacement aortic valve is currently being used for patients in Europe, where it competes with another similar device marketed by
Medtronic Inc.,
MDT 0.16%
of Minneapolis, Minn.

Heart at Work

The aortic valve allows blood to flow from the heart's left ventricle to the brain and body.

When the valve doesn't open and close properly, a progressive condition known as aortic stenosis, a person may experience chest pain, shortness of breath and difficulty exercising.

An estimated 300,000 mainly older Americans have severe aortic stenosis, which is life threatening.

The standard treatment for severe cases is valve replacement through openheart surgery. For about one out of three patients, such major surgery can be too risky, and there is no effective treatment.

An experimental treatment that avoids open-heart surgery is being prepared for FDA approval. The procedure works by threading a replacement valve attached to a catheter through patients' arteries until it reaches the heart.

Source: Edwards Lifesciences Corp.

Medtronic also won U.S. regulatory approval this year for a transcatheter device to replace the pulmonary valve in patients born with a heart defect. That was the first approval in the U.S. for a heart valve that can be implanted without open-heart surgery.

The results of the U.S. study of the Edwards device, known as the Partner trial, will be presented Thursday at the Transcatheter Cardiovascular Therapeutics conference in Washington.

The Edwards replacement valve is made from cow tissue and sits inside a metal frame. The device is crimped onto a balloon catheter, threaded through a leg artery to the heart and expanded inside the old valve.

Another, more invasive delivery method involves passing the valve between the ribs and requires a small heart incision. That method wasn't examined in the latest study data.

Study authors said the higher stroke rate among patients receiving the replacement valve could be due to a number of reasons, including the frail condition of the patients. Several doctors also said the procedure takes time to master and that surgeons are likely to improve their technique with time.

What's more, the replacement valves Edwards is currently aiming at the U.S. market may be too large for some patients. The company expects to introduce smaller devices over time.

Edwards is aiming to apply to the Food and Drug Administration later this year, which could possibly yield approval in 2011. Edwards is also running another segment of the Partner trial that includes more patients and measures transcatheter delivery against surgical valve replacement. The company plans to file an FDA application based on those results, too.